Saha et al. 2016. Int. J. Vehicle Structures & Systems, 8(1), 45-49 International Journal of Vehicle Structures & Systems Available online at www.maftree.org/eja ISSN: 0975-3060 (Print), 0975-3540 (Online) doi: 10.4273/ijvss.8.1.09 © 2016. MechAero Foundation for Technical Research & Education Excellence 45 Modeling and Simulation of Current Fed Interleaved Isolated DC-DC Boost Converter for Fuel Cell Applications Sangit Saha a, b , Abhinav Bhattacharjee a, c and Elangovan Devaraj d a Power Electronics & Drives, VIT University, India b Corresponding Author, Email: sangit.saha2015@vit.ac.in c Email:abhinav.joydeep2015@vit.ac.in d School of Electrical Engg., VIT University, India Email:elangovan.devaraj@vit.ac.in ABSTRACT: In this paper, a current fed, interleaved, high gain, DC-DC converter is proposed for fuel cell applications. The converter also provides electrical isolation between the load and the source by using a transformer. The input features two current fed, full bridge inverters in parallel while the output features two full bridge diode rectifiers in series. By using this topology, the high input current is shared between the two inverters. This enables the use of lower current rating semiconductor devices, reduces switching stresses and reduces the size of magnetic components. It also results in reducing the input current ripple and the output voltage ripple. KEYWORDS: Current fed full bridge; DC-DC; Fuel cell; ICFFBI; Interleaved; Boost converter CITATION: S. Saha, A. Bhattacharjee and E. Devaraj. 2016. Modeling and Simulation of Current Fed Interleaved Isolated DC-DC Boost Converter for Fuel Cell Applications, Int. J. Vehicle Structures & Systems, 8(1), 45-49. doi:10.4273/ijvss.8.1.09. 1. Introduction In recent years, due to the growing energy need and environmental issues, there has been a huge push towards renewable sources of energy. One of the many options that we have among renewable sources is fuel cells. Fuel cells generate power from the reversed reaction of electrolyzed water and give out only water as emission so they are completely non-polluting. There are many kinds of fuel cells. Amongst them proton exchange membrane fuel cells are the most commonly used because they have many merits like lower temperature during operation accordingly leading to rapid turning on and off and rapid reaction to the load change. They also operate at lower pressures, which increase safety. Moreover, they also have a lower emission ratio and higher conversion ratio [1]. A fuel cell normally produces a voltage of around 1V [2]. By stacking many fuel cells together in series, we can get around 40V. But even this voltage is too low for most practical applications and hence it is required to boost this voltage by using appropriate power electronic converters. The input current ripple through the fuel cell stack also needs to be as low as possible [3] because it plays an important role in determining the catalyst lifetime of the fuel cell plates [4]. Hence, having a power electronic converter between the load and the fuel cell is vital in order to satisfy these requirements. In addition to this, it also needs to be ensured that the fuel cell is always operating in the linear region so that the change in input voltage with load is around 2%. There are many converter topologies that can be used to boost the voltage from a fuel cell. We have chosen a high gain, interleaved, full bridge, isolated converter (ICFFBI Converter) by taking into account the requirements of the system. The input features two current fed full bridge inverters connected in parallel and each operating with a phase difference of 180 degrees. This enables the use of less expensive and lower current rating MOSFETs and source inductances as the high input current from the fuel cell is shared equally by the two inverters. It also reduces the stress on the switches during switching. Most importantly, it helps in reducing the ripple factor in the input current which is vital for the longevity of the fuel cell. A high operating frequency of 100 kHz is chosen so that the size of the magnetic components can be kept small and the circuit can be made compact. Two high frequency transformers having turns ratio of 1:2 are used to double the inverter output. In addition to this, the transformers also provide electrical isolation between the high voltage output side and the low voltage input side. This is fed to two full bridge diode rectifiers connected in series so that the voltage from both the stages is added up and fed to the load. Since we are using current fed inverters, it is possible to increase the voltage gain further by charging the source inductance between half cycles by using a duty cycle above 0.5 [6-7]. The concept of interleaving comes with many other benefits like reduction of peak current in the transformer windings, reduced heat sink requirements due to separation of heat generating components, improved form factor and reduced EMI as a result of the reduced